1. Field of the Invention
The present invention relates to a vehicular control apparatus and method for controlling a vehicle that is provided with a power train of which driving force control is performed in which various physical quantities are used to perform the control. The present invention particularly relates to a vehicular control apparatus and method that make it possible to accurately and properly determine whether the vehicle is in an idling state.
2. Description of the Related Art
In the vehicle that is provided with an automatic transmission and an engine that can control the engine output torque independently of the accelerator pedal operation by the driver, there is a technical concept in which desired positive or negative driving torque is realized using the engine torque and the gear ratio of the automatic transmission. The desired positive or negative driving torque is calculated based on the depression amount of the accelerator pedal operated by the driver and the operational condition of the vehicle, etc. This concept is referred to as the “driving force control”. The control methods such as “driving force request type”, “driving force demand type”, and “torque demand type” controls are also other types of the driving force control.
The torque demand type control apparatus of the engine calculates the desired torque of the engine based on the depression amount of the accelerator pedal, the engine speed, and the external loads, and controls the fuel injection amount and the air supply amount according to the calculated, desired torque.
In actual operation, the torque demand type control apparatus of the engine as described above calculates the desired torque production by adding the torque loss, such as friction torque, that is the loss caused in the engine and the power train, to the required output torque, and controls the fuel injection amount and the air supply amount so as to actually produce the desired torque.
According to the torque demand type control apparatus of the engine, the engine torque, which is the physical quantity that directly influences the control of the vehicle, is set as a reference value for controlling the vehicle, so that the drivability can be improved, e.g., the steering feel can be always constant.
Japanese Patent Application Publication No. 2005-178626 (JP-A-2005-178626) discloses the integrated control system for a vehicle that improves the failsafe characteristics in the torque demand type control apparatus of the engine described above. The integrated control system for a vehicle includes: a plurality of control units that control the traveling state of the vehicle based on the request made by operation; and a processing unit that generates information used by each of the control units when there is a request for inhibiting operation of the vehicle in accordance with the location information of the vehicle, and outputs the generated information to each of the control units. Each control unit includes: a detection means for detecting a request for operating at least one of the control units; and a calculating means for calculating information regarding the desired control value to operate the actuator provided for each control unit using at least either of information generated by the processing unit or the operational request detected by the detection means.
According to the integrated control system for a vehicle, the drive system, the brake system, and the steering system are integrated to control the vehicle. For example, the integrated control system adjusts a difference between the required driving force that is calculated based on the operation amount of the accelerator pedal operated by the driver and the required driving force calculated by the driving support system, and then calculates command values to be sent to the actuators that control the output torque of the driving power source and the gear ratio of the transmission.
However, when it is determined that the vehicle is in an idling state based on a request for deceleration made by the driver, etc., the fuel-cut control, the deceleration slip control, the neutral control, and the brake control are performed. Conventionally, in many cases, whether the vehicle is in an idling state is determined based on the throttle opening degree using steps such as prediction of the idling state or estimation of a driver's intention, etc.
In the driving force control, a plurality of physical quantities are used to perform control, and therefore, the determination as to whether the vehicle is in an idling state that is made based on each physical quantity becomes important in controlling vehicles. However, because different physical quantities result in different idling state determination results (that is, it is impossible to determine whether the vehicle is in an idling state using the throttle opening degree only as in the conventional manner), it may be possibly determined that the vehicle is not in an idling state although the throttle opening degree is equal to or below a predetermined opening degree which indicates that the vehicle is in an idling state. Specifically, in the driving force control in which differences among a plurality of the physical quantities are adjusted, if it is determined whether the vehicle is in an idling state based on the throttle opening degree only, differences among a plurality of the physical quantities may be adjusted under the condition where one physical quantity indicates that the vehicle is in an idling state, but another physical quantity indicates that the vehicle is not in the idling state.